Coated acoustic tile and process therefor



Oct. 7, 1958 A. GlLcHRlsT ETAL 2,855,327

COATED ACOUSTIC TILE AND PROCESS THEREFQR Filed Jan. 2e, 195e vvvvvvvv 0000000900@ @@@QOQWQ www www MOM i United States Patent COATED ACOUSTIC TILE AND PROCESS THEREFOR Allan E. Gilchrist, Fairview Park, and Donald T. Rehm', Lakewood, Ohio, assipors to The Glidden Company, Cleveland, Ohio, a corporation of Ohio Application January 26,1956, Serial No. 561,594 s Claims. (CL 117-45) This invention relates to` coated fibrous-acoustic mate; n'al and to a process for preparing same, and itrelates more particularly tol coated acoustic material preparedl from low density, fibrous, open-texture material in the form of tile, board, etc.

Sound-absorbing material, commonly prepared in the form of Atile is necessarily of an open-texture to allow sound waves to penetrate thereinto and be absorbed. Such macroscopically-porons material is commonly prepared of fibrous materials loosely matted together by means of binders, but granular material, like granulated cork, is sometimes formed by means of adhesive binders into board and tile so as to present many pores and interstices which improve the sound absorbing qualities. The appearance, color and texture of these and likeacoustic materials is frequently inappropriate in a'decorative sense and is desirably concealed occasionally by a pigmented surface coat having elective hiding qualities. The application of such a hiding coat when continuous, however, tends to block the sound absorbing pores and interstices, and hence impairs the sound-absorbing qualities. In some instances this effect can be counteracted by punching or drilling holes through the coating or coated board, panel or tile, the number, size and disposition of the holes being chosen to give a regular or random pattern which'has decorative appeal but which still permits the tile to function effectively as a sound absorber. Such a punching or drilling operation not only adds to the cost of preparing the acoustic material'but also creates a surfaceon the finished article which is diiiicult to recoat when the original coating becomes stained or when one desires to' change' its color. This is because the mouths of the manyholes tend to become clogged with the new coatingmaterial, and hence to be less effective for sound absorbing .purposes. lt is also difficult to clean the coated article (as by washing) because the holes retain some washwater which later runs back to the surface and creates'a fresh ring of strain around each hole.

According to the presentl invention, punchingv can'be eliminated and cleaning' and/ or recoating can be made easier, While yet retaining the sound absorbency substaniially unimpaired. These beneiits' are accomplished by' coating the acoustic material' originally with a liquid pigmented composition which does not penetrate into material and by applying such original coating in'a di`s`- continuous pattern so as to leavepredetermined portions'` of the material uncoated. When a second coating is` sub` sequently applied, if it is one designed for the purposesol as to penetrate into `the uncoatedareas, then 'the' coated areas are covered but the uncoated lareas remainopen, i. e., still present most of the original' porous structure.`

Accordingly, it is anobject of this 'inventiorito'provide acoustic material which is originally coated discontinuously with 4a non-penetrating .coatingso as to providea discontinuous surface coat which hides predetermined portions of the surface while leaving other'portionsun-y coated.

Another object is to provide coated acoustic material ICC 2 of the type just described which is additionally coated with a penetrating coating -composition-adaptedto sink into the originaly uncoated areas, thereby to retain the latter areas essentially uniinpaired in sound absorbency.

A further object is' to provide a process for preparing coated acoustic material of xthe 1 types described.

These and other objects'y will beunderstood more fully from the followingdescriptionfof ourinventiontakenfin conjunction with' the attached drawings'in' which:

Fig.v I is aplan-view of an acoustic tile-'which has been coated -discontinuou'slyv` wit-h i a substantiallynon-penetratingv coatingcomp'os'itiom-a portion havingl been broken away toreveal the acoustic material:y

Fig. Ilv is a fragmentary vertical sectional view'of the tile of Fig. I taken on the line II--lI, and greatly enlarged in its vertical dimensions. A v

Fig. III is a' fragmentary' sectional view corresponding to Fig. IIlbut showi'r'iga' secnd--coating-which has been applied t' y' the tile" of Figs." I and lI, .said second coating being one having penetrating qualities.-

Referring now to'Figsff Ian'd IIwhich represent a as A (identified below) so as to leraveareas 3, 3 uncoated.

The areas `of appliednon-perietrating coating material are here-shown to-have--a--dianioid shape with the diamonds arriiged'o a regulrwcli'eckerboard pattern.` It willy be understood, of-course; thatdtlieptterncan'be variedy accordingfto individual taste orpreferenceasflong as suicient uneoat'ed areasf 3; -3 are leftto functin'inza sound absorbing'manher.' Theptt'ern whi'c'li'isiselected canbe' applied by a screen-process, by using a patterned roller, by spraying' with 'a' stencil; or by other'ob'vious methods. The coating: composition which forms' Ythe lilrn 2, as noted above, has been' forinulatedso as' to' have substantiallyL non-penetrating qualities; that is, whenappled to the surface of'tile 1, it remains on" the surface without sinking into the' interior. A typical" formulation having this quality isV represented by Compositin A, the proportions being given in parts by weight:

Composition A For application, this composition is reducedwith water as required (e. g., between 10:1 and about 4:1). The applied coating has fire retardant qualities as well as being1 durable and resistant to washing. Because of its non'- penetrating quality, when Composition A"(suitably reduced) is applied to-tile'l, as by'a patterned roller e or by spraying through amask, the lm offliquid'composition remaining on the surface does not'encroach on the areas 3, 3 which are to be' left uncoated. The so-applied, discontinuous lm 2 seals the surface'fwith which it'l is in contact and provides a base upon'which apenetrating (usually a hiding) film' 4, such as Composition -B` below,v

can be applied without sinking intoV the interior of tile 1. Fig; III illustratesl the'tile'atter suchv of penetratingtype' Composition B has beenv appled Thus the latter composition forms a li'n 4 on top of the non-penetrating film 2,Y but wherever it Awas applied to the uncoated areas 3, 3, it has penetrated into the tile and has not formed any continuous surface film. These areas consequently remain exposed to sound waves and can continue to function as sound-absorbing areas.

It will be apparent that the penetrating-type Composition B can be applied in a continuous film, as by brushing, spraying, etc., since the non-penetrating film 2 has determined the pattern which will remain when the penetrating coating has dried. It could, of course, be applied in a discontinuous film by the same method used to deposit the lm 2, care being taken to keep the pattern of film 4 in register with that of film 2. This is unnecessary, however, as will be understood. lt is much easier to apply a continuous film and let it sink into the uncoated areas 3, 3. The following is a typical formulation of a suitable pene trating-type coating composition, the proportions being given in parts by weight:

Composition B Finished composition weighs 13.3 pounds per gallon. For spray application, it is reduced with water at a rate of about 4:1. For other application methods, reduction can be as needed to secure penetration. To improve penetration, small amounts of anionic and/or non-ionic surface active agents can be added. Usually amounts up to 1% by weight are sufficient.

It will be recognized that the majority of conventional coating compositions are of the penetrating-type and hence need no extended discussion, and that the non-penetrating type represents a minor group wherein the formulation is such that non-penetrating qualities result. if there is any doubt about the type of coating which one has at hand, a simple test application on the surface of the acoustic material will reveal whether it penetrates thereinto or does not penetrate.

From what has been pointed out above, it will be apparent thatthe non-penetrating composition which is employed can be either pigmented or unpigmented; that is, it can deposit a clear film, or one which carries enough pigment to provide some hiding of the underlying tile. Usually a pigmented composition would be used, since hiding is sought. However, the pigments employed even then need not be of the high-hiding types like titanium dioxide, but instead can be cheaper pigments and/or fillers such as are shown in the above formulation of Composition A. Highhiding pigments can be used advantageously in Composition B, especially when the patterned material is to be recoated to change its color.

Formulations of non-penetrating compositions, analogous to Composition A, are well known to those skilled in the art and need no extended discussion. Many different film-forming materials can be used in such coatings7 as protein, starches, methyl cellulose, polyvinyl alcohol. acrylic gum, natural gums, alginates, and other colloidal materials. Many film-forming materials which by themselves would be unsuitable can be used, however, if dispersed in a carrier such as water to provide an emulsion having specially adjusted surface tension and viscosity i qualities.

l The compositions described in U. S. Patents 2,709,689, 2,101,066, 2,591,904, 2,511,782, 2,450,534, 2,342,581, 2,337,013, 2,321,937-9 and 2,241,174 represent a few of the numerous non-penetrating materials which can be used in practicing the present invention in addition t0 Composition A, supra.

Likewise, formulations of penetrating compositions analogous to Composition B are well known and need no discussion, except to point out that such compositions are desirably formulated with filmforming materials which will impart some washand scrub-resistance since it is generally desirable to provide a film 4 which can be washed occasionally or at least sponge-cleaned.

it will be apparent that this invention makes it possible to coat acoustic material in a wide variety of functional and decorative patterns while yet widely varying the ratio of coated area to uncoated area. it also makes it possible for acoustic material to be coated without requiring the expensive operation of punching or drilling the coated material to restore its acoustic effectiveness. Moreover. it simplifies the task of recoating acoustical installations when their appearance is to be freshened, or when a different color is desired, since the acoustically-effective pattern on the tiles or board of the installation will not be impaired when a penetrating-type coating is brushed, sprayed or otherwise applied in a continuous wet lm.

From what has been said hereinabove, it will he apparent that the objective is in general to provide a decorative appearance or pattern to the surface of acoustic material while yet not unduly impairing the acoustic qualities. Ordinarily at least about 25% of the surface of the acoustic material should remain uncoated with the nonpenetrating-type of coating so as to retain useful sound absorbing qualities'. lf decorative quality is less significant than acoustic quality, then as much as or more can be retained uncoated, Even when as much as 75% of the area is coated, however, the acoustic material can yet exhibit greater sound absorbency than would be expected from the 25% of uncoated area. T his is because each of the individual spots or areas of non-penetrating coating can function independently as a small diaphragm, the vibration of which can absorb and dissipate energy from an impinging sound wave. Such diaphragm action is materially reduced when the coating is continuous over the surface of the acoustic material. Moreover, our discontinuous coating of non-penetrating material can be arranged in a multitude of diverse patterns some of which will have better sound-dissipating properties (due to combinations of diaphragm action, edge effects and intercoating absorbency) than other patterns. lt is therefore possible to choose and provide patterns which can be more effective for certain service situations than if a pattern were chosen solely for its decorative or esthetic merits.

Having now described the invention, what is claimed is:

l. Coated acoustic material having a macroscopicallyporous, sound-absorbing, open texture adjacent to and below a surface thereof and having a solidified, discontinuous coating adhered to selected portions of said surface and having adjacent portions thereof uncoated; said coating having been deposited initially in the form of a wet lm from a liquid coating composition characterized by possessing substantially non-penetrating qualities when applied to said surface, the surface of said uncoated portions being contiguous with the adjacent surface portions of the acoustic material which carry said solidified coating.

2. Coated acoustic material as claimed in claim l having had another layer of solidified coating material applied thereto uniformly over said coated and uncoated portions of said surface, said layer having been deposited from a. liquid coating composition having penetrating qualities when applied to said uncoated portions of the surface of said acoustic material.

v3. Coated Aacoustic material as claimed in claim 1 wherein the discontinuous, solidied coating which is adhered to said surface covers between about 25% and 75% of the total surface.

4. Coated acoustic material as claimed in claim 3 having had another layer of solidified coating material applied thereto uniformly over said coated and uncoated portions of said surface, said layer having been deposited from aliquid coating composition having penetrating qualities when applied to said uncoated portions of the surface of said acoustic material.

5. The method of coating acoustic material having a macroscopically porous open texture, which comprises the steps of: applying a substantially non-penetrating wet coating of film-forming material to a surface of'said material in a discontinuous pattern, thereby to coat predetermined portions of said surface while leaving other portions uncoated, drying said applied coating, and then applying a liquid, penetrating-type, pigmented, hiding References Cited in the file of this patent UNITED STATES PATENTS 2,154,943 King Apr. 18, 1939 FOREIGN PATENTS 1,056,450 France Oct. 2l, 1953 

1. COATED ACOUSTIC MATERIAL HAVING A MACROSCOPICALLYPOROUS, SOUND-ABSORBING, OPEN TEXTURE ADJACENT TO AND BELOW A SURFACE THEREOF AND HAVING A SOLIDIFIED, DISCONTINUOUS COATING ADHERED TO SELECTED PORTIONS OF SAID SURFACE AND HAVING ADJACENT PORTIONS THEREOF UNCOATED; SAID COATING HAVING BEEN DEPOSITED INITIALLY IN THE FORM OF A WET FILM FROM A LIQUID COATING COMPOSITION CHARACTERIZED BY POSSESSING SUBSTANTIALLY NON-PENETRATING QUAL- 